著者

檜垣 強

出版者

公益社団法人 日本地震学会

雑誌

地震 第2輯 (ISSN:00371114)

巻号頁・発行日

vol.26, no.1, pp.93-100, 1973-06-30 (Released:2010-03-11)

参考文献数

4

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A pulse-like minute oscillation happened to be recorded simultaneously at the four temporary seismic stations installed 2.5-9.0km apart each other, near Kumamoto city. The oscillation lasted only half a second which appears to be too short against the common understanding of earthquake phenomena. Amplitude is incredibly small as well.However, there are a few evidences to support that it is an “earthquake.” It is followed by an earthquake of moderate size, the observed time intervals between two events being about 18 seconds at every stations. The observed directions of initial P motion are reversed between these two events at every stations suggesting that they are physically connected. The hypocenter of this micro-earthquake can be accurately located by seismic technique.The provisional estimation of its magnitude has shown that it is less than -3.